I was previously calculating my HR zones off of my maximum heart rate (188bpm), I’ve since learned that finding my LTHR would be more accurate. According to internals.icu, my LTHR is 169. (I’m not quite sure how intervals.icu calculates LTHR and uses my manually inputted Max HR to calculate the HR zones it uses?)
You can see they differ a fair bit, but these two differ significantly from the zones given in intervals.icu. For example, in Zone 2 (where I do most of my training) FormBeat’s LTHR has me at 117-142, whereas intervals has my Zone 2 at 136-151 - which seems high to me for my Zone 2.
For info: My most recent tamp test from 3 weeks puts my FTP at 173w. 44 y/o male, 188 Max HR, 54 Resting HR, 6ft 1in, 82kg/182lbs. 3 months into base training after 2 year lay off.)
There are numerous zone systems… Historically zones were first based on speed/pace, measured with a chrono. Athletes used RPE for internal load. Then came GPS devices with better and more practical ways of measuring speed/pace. Then came HR monitors allowing to define the zones a bit better and get a better idea of internal load. And then came power meters that allowed comparing internal load with external load.
All this lead to a broad range of different zones, depending on what was available AND of the desired outcome. Athletes training for long events, ultra’s, triathlons, Iron Man have very different goals compared to those training TT, Cyclocross, criteriums…
Ultra-athletes have very little interest in anything beyond VO2max, while Cyclocrosser’s have this high on their list. Thus coaches developed zones that applied best to the goals. Some swear by HR, others by Power and or Pace.
The thing is, you need to decide what will be your ‘anchor’. And then you can manually adapt the other metric zones to correlate as best as possible. All this while accounting for the flaws of each metric. HR for example lags a lot, and is unusable for anaerobic efforts. So why would you want to make a HR zone for anaerobic if the measured HR is way of due to the lag???
I am mostly interested in long events and anchor almost all my training on HR zones. But I do use Power for both running and cycling to calculate load. Because the little high intensity work I do would otherwise not be reflected correctly in the load.
There’s a new wave going on now that wants to simplify the zone system. It’s based on 2 physiological anchor points. AeT, aerobic HR and AT, anaerobic HR. Resulting in a 3 main zones, Low intensity, Medium intensity and High intensity. The base of a training plan simply uses those three zones and then you specifically divide further each zone to target the specific targets that are important in your discipline. The number one rule is that you do 4 out of 5 sessions in the Low intensity zone and the fifth session is a Medium or High intensity session depending on the training phase you’re in and on the specific demands of your targeted events.
An example for the Low intensity zone: Do lots of training in the range of 5-15 bpm below your AeT. If you need a recovery session, stay 10-20 beats below AeT. For Medium intensity, during base phase, stay at the lower range for longer intervals. During build phase, increase intensity to the zone just below AT.
These are simple straightforward examples, but there are loads of alternatives.
For High intensity , it is clear that you can’t use HR. You need to use power or pace to better target your training or you are ‘guessing’ if the intensity is the correct one.
Regarding your TIZ distribution: There’s not a lot of data yet and if you view this in the perspective of the above mentioned three zone system, things look quite good. Z1/Z2 is not a strict limit, it’s a ‘guide’ to make sure that you don’t ‘overdo’ a recovery ride. If you look at your data like it’s done in the bottom (Z1 + Z2 vs Z3 + Z4 vs Z5 and above), it’s quite balanced.
If you want them to be more correlated you can do a lab test for ftp and hr zones. For now your z2 is just a population based avg and can be 10bpms off one way or the other. But even if you do a proper lab test pelase remember that if you ride z2 for example, and coast for 10 sec, your hr is still in your z2 zone but power is not, and on the other side you can rise your power for 10sec to z3/z4 zone and still your hr will stay at z2, that makes a huge differenve when viewed from a monthly cummulated perspective.
Just tryint to explain that more data is ok but you should use it in a way it makes sense (for you mainly). At the end it is mostly about your RPE anyways. If you ride same/similar course on a weekly basis let’s say at z2, you can easily see that depending on your current daily form, your power for a given hr can be +/-30w, and even if you switch to going by hr you will find quickly that on some days it is impossible to hold your standard z2 hr number. And on some days (like once/twice a year) all that data is rubish anyways bc your legs go like crazy, and noone knows why.
@MedTechCD can you give a link or some more info about that new wave thing ? sound s interesting.
It’s basically the Polarized approach by Seiler. His ‘pure’ approach of that, not the numerous ‘interpretations’ by others abusing the 80/20, 90/10, Medium/High intensity story.
A very good source, in my opinion, is
But if you don’t like ‘Old School’ explanations, it might seem boring…
It’s also somewhat biased on Triathlon, Iron Man training. Mainly long endurance events. But hey, that’s what most beginners and even intermediate non-pro’s should be paying attention to. Pro’s should listen to their proper coaches because they know what their athletes need.
sounds good, definitly will check thanks!
trying to decide if I need mid intensity during the season (last season ended up destryed towards the end) and was thinking about moving more towards polarized. I ride for myself mostly anyways so the more time during the season I;m fit the better even if it cuts top of my ftp a bit
Definitely confusing. I’ve been using Heart Rate Reserve which is what Dr. David Seiler prefers, or at least uses for his studies. Apple Watch uses HRR too for zones. Strava, which I use to record my rides, uses Maximum Heart Rate. Intervals.icu uses LTHR. Things used to be so much simpler.
All I can figure from all this is that hitting the middle of any zone will coordinate closely with any of the other zone models. What few points of difference there might be in the prevalence of one physiological system over another is of minor importance. The data actually charts as a curve and isn’t really ending and starting. Scientists have to write down numbers and they do. That leads to lines which creates zones.
But ultimately, and Dr. David Seiler says as much, they are just trying to catch up and quantify what trainers have known for a long time is a good training regime. The data from the studies is the same, only the charts it is graphed on are different.
I don’t believe we need to overthink this.
I don’t think Intervals.icu calculation is accurate for LTHR. Nowhere else can I find anyone calculating LTHR from MaxHR.
Do you calculate load based on HR or power? If HR, do you see any changes to your LTHR as you train or detrain. I’m asking because I calculate load based on LTHR and wonder if I need to do an LTHR-test more often or if that number mostly stays the same but the pace at LTHR changes as my training progresses?
Wherever possible, I use Power for load because it is the most granular metric.
LTHR may change quite a bit if you’re a novice with poor fitness. After a 6-12 months of regular training, LTHR isn’t going change much. At most a couple of beats. Pace at LTHR should significantly change if you have a good training schedule and are a beginner. If you have been competitive for years, pace will change much slower.
I’m really impressed with all the intelligent input above. Thank you. I understand that there is a lot more subjectivity to LTHR and heart rate zones. As @MedTechCD points out, this is more useful for him (and me) at the lower zones, which is where I spend the majority of my time training.
What I can’t seem to reconcile is the huge disparity between the numbers and percentages given by intervals.icu and all of the resources in finding online. For example, intervals is suggesting my Zone 2 HR should be 80% - 89% of Max/LTHR which for me is 136 - 151bpm. But all the other info I’m finding online is suggesting Zone 2 should be about 69-83% of Max/LTHR which puts my Zone 2 efforts around 117 - 139 bpm. I’m not sure what to trust - and, if I believe the intervals.icu to be incorrect, should I manually go in and change the heart rate zones in the settings?
It’s 80-89% of LTHR or 69-83 of max. Those should be closer together.
It’s based on the fact that on average the LTHR is about 90-95% of max.
Those are all estimates and averages based on large population. You, yourself may be quite far from that.
When it comes to Low Intensity (I hate using the Z2 terminologie because Z2 can have a very different meaning in different zone systems), the sure way of doing productive base training without much risk of going too high, is the MAF method. 180 minus age. Work with that as an upper limit and stay within 5-15 bpm lower. You may be surprised by how ‘easy’ it is, but it is the correct zone for building base. If you think this is way too easy, do it for 3-4 hours and come back with your comments ;-).
Thanks @MedTechCD. My 69-83% of max is 130 - 156bpm, which are figures that are higher again. I’ll look into your MAF method, which puts by upper limit at 136bpm - a figure which feels closer to what I see while doing Z2 FTP efforts of 2hrs+.
LTHR is the average HR from from a steady-state effort, aka the “FTP test”, or about 30-70 minutes; the key is steady state. While this is also an estimate, “many” athletes don’t want to do the effort, and prefer to use a shorter duration to estimate their FTP, and then LTHR.
The settings in many applications are based on a population curve, so using this could be resulting in easy efforts being too hard. LT1 is lower than most think it is, and is relatively easy to find using a few tools (AlphaHRV) and tips (breathing).
The MAF method puts me within 2 bpm of my LT1, which is much lower than what Garmin’s and TrainingPeaks’ defaults show (12-15bpm higher). Breathing changes also become noticeable at the same level.
As @MedTechCD has mentioned, it should feel “too easy”.
sound s interesting.
thanks!